Strangeness enhancement at midrapidity in Pb-Pb collisions at 158 A GeV/c: a comparison with VENUS and RQMD models

Recently the WA97 Collaboration has measured K0S, Λ, Ξ, Ω and negative particle yields and transverse mass spectra at central rapidity in Pb-Pb and p-Pb collisions at 158 A GeV/c. These results are compared with the predictions of two of the most widely used event generators for heavy-ion collisions: VENUS 4.12 and RQMD 2.3. Both models predict that enhancements increase with the strangeness content of the particle. They fail, however, to reproduce completely the measured values of yields at central rapidity. In particular, for multistrange particles, VENUS fails to reproduce both the p-Pb and the Pb-Pb data, while RQMD works for p-Pb collisions but seems to be unable to reproduce the Ω data in Pb-Pb collisions. Moreover, the predicted behavior for strangeness production as a function of the centrality of the collision appears to be different from the observed behavior. (orig.)